Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University

Jun WANG

Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University

Md. Rubel RANA

Biological Science Course, Graduate School of Science, National University Corporation Shizuoka University

Mikiko NAKASHIMA

Department of Biology, Faculty of Science, National University Corporation Shizuoka University

Toshinobu TOKUMOTO

Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University Biological Science Course, Graduate School of Science, National University Corporation Shizuoka University Department of Biology, Faculty of Science, National University Corporation Shizuoka University

Oocyte maturation in medaka is induced by the maturation-inducing hormone (MIH) via its membrane receptor. The most likely candidates for the membrane receptor are membrane progestin receptors (mPRs). In order to characterize the mPRα subtype of medaka, a human cell line expressing the mPRα gene of medaka was established and its steroid binding property was assessed. The α subtype exhibited high binding affinity for 17,20β-DHP, the MIH in medaka. Treatment with a morpholino antisense oligonucleotide to mPRα blocked oocyte maturation in vivo. These results suggest that the medaka mPRα protein acts as an intermediary during MIH-induced oocyte maturation in medaka in a manner similar to that described previously for fish species.